diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mach-omap2/clock.c | 198 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/clock.h | 5 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/clock24xx.c | 12 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/clock24xx.h | 17 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/clock34xx.h | 36 |
5 files changed, 250 insertions, 18 deletions
diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c index 0243480e8bfe..15675bce8012 100644 --- a/arch/arm/mach-omap2/clock.c +++ b/arch/arm/mach-omap2/clock.c @@ -41,6 +41,24 @@ #define MAX_CLOCK_ENABLE_WAIT 100000 +/* DPLL rate rounding: minimum DPLL multiplier, divider values */ +#define DPLL_MIN_MULTIPLIER 1 +#define DPLL_MIN_DIVIDER 1 + +/* Possible error results from _dpll_test_mult */ +#define DPLL_MULT_UNDERFLOW (1 << 0) + +/* + * Scale factor to mitigate roundoff errors in DPLL rate rounding. + * The higher the scale factor, the greater the risk of arithmetic overflow, + * but the closer the rounded rate to the target rate. DPLL_SCALE_FACTOR + * must be a power of DPLL_SCALE_BASE. + */ +#define DPLL_SCALE_FACTOR 64 +#define DPLL_SCALE_BASE 2 +#define DPLL_ROUNDING_VAL ((DPLL_SCALE_BASE / 2) * \ + (DPLL_SCALE_FACTOR / DPLL_SCALE_BASE)) + u8 cpu_mask; /*------------------------------------------------------------------------- @@ -95,7 +113,7 @@ u32 omap2_get_dpll_rate(struct clk *clk) { long long dpll_clk; u32 dpll_mult, dpll_div, dpll; - const struct dpll_data *dd; + struct dpll_data *dd; dd = clk->dpll_data; /* REVISIT: What do we return on error? */ @@ -724,6 +742,184 @@ int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent) return 0; } +/* DPLL rate rounding code */ + +/** + * omap2_dpll_set_rate_tolerance: set the error tolerance during rate rounding + * @clk: struct clk * of the DPLL + * @tolerance: maximum rate error tolerance + * + * Set the maximum DPLL rate error tolerance for the rate rounding + * algorithm. The rate tolerance is an attempt to balance DPLL power + * saving (the least divider value "n") vs. rate fidelity (the least + * difference between the desired DPLL target rate and the rounded + * rate out of the algorithm). So, increasing the tolerance is likely + * to decrease DPLL power consumption and increase DPLL rate error. + * Returns -EINVAL if provided a null clock ptr or a clk that is not a + * DPLL; or 0 upon success. + */ +int omap2_dpll_set_rate_tolerance(struct clk *clk, unsigned int tolerance) +{ + if (!clk || !clk->dpll_data) + return -EINVAL; + + clk->dpll_data->rate_tolerance = tolerance; + + return 0; +} + +static unsigned long _dpll_compute_new_rate(unsigned long parent_rate, unsigned int m, unsigned int n) +{ + unsigned long long num; + + num = (unsigned long long)parent_rate * m; + do_div(num, n); + return num; +} + +/* + * _dpll_test_mult - test a DPLL multiplier value + * @m: pointer to the DPLL m (multiplier) value under test + * @n: current DPLL n (divider) value under test + * @new_rate: pointer to storage for the resulting rounded rate + * @target_rate: the desired DPLL rate + * @parent_rate: the DPLL's parent clock rate + * + * This code tests a DPLL multiplier value, ensuring that the + * resulting rate will not be higher than the target_rate, and that + * the multiplier value itself is valid for the DPLL. Initially, the + * integer pointed to by the m argument should be prescaled by + * multiplying by DPLL_SCALE_FACTOR. The code will replace this with + * a non-scaled m upon return. This non-scaled m will result in a + * new_rate as close as possible to target_rate (but not greater than + * target_rate) given the current (parent_rate, n, prescaled m) + * triple. Returns DPLL_MULT_UNDERFLOW in the event that the + * non-scaled m attempted to underflow, which can allow the calling + * function to bail out early; or 0 upon success. + */ +static int _dpll_test_mult(int *m, int n, unsigned long *new_rate, + unsigned long target_rate, + unsigned long parent_rate) +{ + int flags = 0, carry = 0; + + /* Unscale m and round if necessary */ + if (*m % DPLL_SCALE_FACTOR >= DPLL_ROUNDING_VAL) + carry = 1; + *m = (*m / DPLL_SCALE_FACTOR) + carry; + + /* + * The new rate must be <= the target rate to avoid programming + * a rate that is impossible for the hardware to handle + */ + *new_rate = _dpll_compute_new_rate(parent_rate, *m, n); + if (*new_rate > target_rate) { + (*m)--; + *new_rate = 0; + } + + /* Guard against m underflow */ + if (*m < DPLL_MIN_MULTIPLIER) { + *m = DPLL_MIN_MULTIPLIER; + *new_rate = 0; + flags = DPLL_MULT_UNDERFLOW; + } + + if (*new_rate == 0) + *new_rate = _dpll_compute_new_rate(parent_rate, *m, n); + + return flags; +} + +/** + * omap2_dpll_round_rate - round a target rate for an OMAP DPLL + * @clk: struct clk * for a DPLL + * @target_rate: desired DPLL clock rate + * + * Given a DPLL, a desired target rate, and a rate tolerance, round + * the target rate to a possible, programmable rate for this DPLL. + * Rate tolerance is assumed to be set by the caller before this + * function is called. Attempts to select the minimum possible n + * within the tolerance to reduce power consumption. Stores the + * computed (m, n) in the DPLL's dpll_data structure so set_rate() + * will not need to call this (expensive) function again. Returns ~0 + * if the target rate cannot be rounded, either because the rate is + * too low or because the rate tolerance is set too tightly; or the + * rounded rate upon success. + */ +long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate) +{ + int m, n, r, e, scaled_max_m; + unsigned long scaled_rt_rp, new_rate; + int min_e = -1, min_e_m = -1, min_e_n = -1; + + if (!clk || !clk->dpll_data) + return ~0; + + pr_debug("clock: starting DPLL round_rate for clock %s, target rate " + "%ld\n", clk->name, target_rate); + + scaled_rt_rp = target_rate / (clk->parent->rate / DPLL_SCALE_FACTOR); + scaled_max_m = clk->dpll_data->max_multiplier * DPLL_SCALE_FACTOR; + + clk->dpll_data->last_rounded_rate = 0; + + for (n = clk->dpll_data->max_divider; n >= DPLL_MIN_DIVIDER; n--) { + + /* Compute the scaled DPLL multiplier, based on the divider */ + m = scaled_rt_rp * n; + + /* + * Since we're counting n down, a m overflow means we can + * can immediately skip to the next n + */ + if (m > scaled_max_m) + continue; + + r = _dpll_test_mult(&m, n, &new_rate, target_rate, + clk->parent->rate); + + e = target_rate - new_rate; + pr_debug("clock: n = %d: m = %d: rate error is %d " + "(new_rate = %ld)\n", n, m, e, new_rate); + + if (min_e == -1 || + min_e >= (int)(abs(e) - clk->dpll_data->rate_tolerance)) { + min_e = e; + min_e_m = m; + min_e_n = n; + + pr_debug("clock: found new least error %d\n", min_e); + } + + /* + * Since we're counting n down, a m underflow means we + * can bail out completely (since as n decreases in + * the next iteration, there's no way that m can + * increase beyond the current m) + */ + if (r & DPLL_MULT_UNDERFLOW) + break; + } + + if (min_e < 0) { + pr_debug("clock: error: target rate or tolerance too low\n"); + return ~0; + } + + clk->dpll_data->last_rounded_m = min_e_m; + clk->dpll_data->last_rounded_n = min_e_n; + clk->dpll_data->last_rounded_rate = + _dpll_compute_new_rate(clk->parent->rate, min_e_m, min_e_n); + + pr_debug("clock: final least error: e = %d, m = %d, n = %d\n", + min_e, min_e_m, min_e_n); + pr_debug("clock: final rate: %ld (target rate: %ld)\n", + clk->dpll_data->last_rounded_rate, target_rate); + + return clk->dpll_data->last_rounded_rate; +} + /*------------------------------------------------------------------------- * Omap2 clock reset and init functions *-------------------------------------------------------------------------*/ diff --git a/arch/arm/mach-omap2/clock.h b/arch/arm/mach-omap2/clock.h index f97948548f29..3cd37cb57c5a 100644 --- a/arch/arm/mach-omap2/clock.h +++ b/arch/arm/mach-omap2/clock.h @@ -18,11 +18,16 @@ #include <asm/arch/clock.h> +/* The maximum error between a target DPLL rate and the rounded rate in Hz */ +#define DEFAULT_DPLL_RATE_TOLERANCE 50000 + int omap2_clk_enable(struct clk *clk); void omap2_clk_disable(struct clk *clk); long omap2_clk_round_rate(struct clk *clk, unsigned long rate); int omap2_clk_set_rate(struct clk *clk, unsigned long rate); int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent); +int omap2_dpll_rate_tolerance_set(struct clk *clk, unsigned int tolerance); +long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate); #ifdef CONFIG_OMAP_RESET_CLOCKS void omap2_clk_disable_unused(struct clk *clk); diff --git a/arch/arm/mach-omap2/clock24xx.c b/arch/arm/mach-omap2/clock24xx.c index ece32d8acba4..aa567876651d 100644 --- a/arch/arm/mach-omap2/clock24xx.c +++ b/arch/arm/mach-omap2/clock24xx.c @@ -154,7 +154,7 @@ static void omap2_clk_fixed_disable(struct clk *clk) * Uses the current prcm set to tell if a rate is valid. * You can go slower, but not faster within a given rate set. */ -static u32 omap2_dpll_round_rate(unsigned long target_rate) +long omap2_dpllcore_round_rate(unsigned long target_rate) { u32 high, low, core_clk_src; @@ -183,14 +183,14 @@ static u32 omap2_dpll_round_rate(unsigned long target_rate) } -static void omap2_dpll_recalc(struct clk *clk) +static void omap2_dpllcore_recalc(struct clk *clk) { clk->rate = omap2_get_dpll_rate_24xx(clk); propagate_rate(clk); } -static int omap2_reprogram_dpll(struct clk *clk, unsigned long rate) +static int omap2_reprogram_dpllcore(struct clk *clk, unsigned long rate) { u32 cur_rate, low, mult, div, valid_rate, done_rate; u32 bypass = 0; @@ -209,7 +209,7 @@ static int omap2_reprogram_dpll(struct clk *clk, unsigned long rate) } else if ((rate == (cur_rate * 2)) && (mult == 1)) { omap2_reprogram_sdrc(CORE_CLK_SRC_DPLL_X2, 1); } else if (rate != cur_rate) { - valid_rate = omap2_dpll_round_rate(rate); + valid_rate = omap2_dpllcore_round_rate(rate); if (valid_rate != rate) goto dpll_exit; @@ -256,7 +256,7 @@ static int omap2_reprogram_dpll(struct clk *clk, unsigned long rate) omap2_init_memory_params(omap2_dll_force_needed()); omap2_reprogram_sdrc(done_rate, 0); } - omap2_dpll_recalc(&dpll_ck); + omap2_dpllcore_recalc(&dpll_ck); ret = 0; dpll_exit: @@ -383,7 +383,7 @@ static int omap2_select_table_rate(struct clk *clk, unsigned long rate) local_irq_restore(flags); } - omap2_dpll_recalc(&dpll_ck); + omap2_dpllcore_recalc(&dpll_ck); return 0; } diff --git a/arch/arm/mach-omap2/clock24xx.h b/arch/arm/mach-omap2/clock24xx.h index 06e1118ddba2..be4e25554e05 100644 --- a/arch/arm/mach-omap2/clock24xx.h +++ b/arch/arm/mach-omap2/clock24xx.h @@ -30,12 +30,12 @@ static long omap2_round_to_table_rate(struct clk *clk, unsigned long rate); static void omap2_sys_clk_recalc(struct clk *clk); static void omap2_osc_clk_recalc(struct clk *clk); static void omap2_sys_clk_recalc(struct clk *clk); -static void omap2_dpll_recalc(struct clk *clk); +static void omap2_dpllcore_recalc(struct clk *clk); static int omap2_clk_fixed_enable(struct clk *clk); static void omap2_clk_fixed_disable(struct clk *clk); static int omap2_enable_osc_ck(struct clk *clk); static void omap2_disable_osc_ck(struct clk *clk); -static int omap2_reprogram_dpll(struct clk *clk, unsigned long rate); +static int omap2_reprogram_dpllcore(struct clk *clk, unsigned long rate); /* Key dividers which make up a PRCM set. Ratio's for a PRCM are mandated. * xtal_speed, dpll_speed, mpu_speed, CM_CLKSEL_MPU,CM_CLKSEL_DSP @@ -665,20 +665,27 @@ static struct clk alt_ck = { /* Typical 54M or 48M, may not exist */ * deal with this */ -static const struct dpll_data dpll_dd = { +static struct dpll_data dpll_dd = { .mult_div1_reg = OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL1), .mult_mask = OMAP24XX_DPLL_MULT_MASK, .div1_mask = OMAP24XX_DPLL_DIV_MASK, + .max_multiplier = 1024, + .max_divider = 16, + .rate_tolerance = DEFAULT_DPLL_RATE_TOLERANCE }; +/* + * XXX Cannot add round_rate here yet, as this is still a composite clock, + * not just a DPLL + */ static struct clk dpll_ck = { .name = "dpll_ck", .parent = &sys_ck, /* Can be func_32k also */ .dpll_data = &dpll_dd, .flags = CLOCK_IN_OMAP242X | CLOCK_IN_OMAP243X | RATE_PROPAGATES | ALWAYS_ENABLED, - .recalc = &omap2_dpll_recalc, - .set_rate = &omap2_reprogram_dpll, + .recalc = &omap2_dpllcore_recalc, + .set_rate = &omap2_reprogram_dpllcore, }; static struct clk apll96_ck = { diff --git a/arch/arm/mach-omap2/clock34xx.h b/arch/arm/mach-omap2/clock34xx.h index e349d48ee807..05757eb032bc 100644 --- a/arch/arm/mach-omap2/clock34xx.h +++ b/arch/arm/mach-omap2/clock34xx.h @@ -35,6 +35,10 @@ static u32 omap3_dpll_autoidle_read(struct clk *clk); static int omap3_noncore_dpll_enable(struct clk *clk); static void omap3_noncore_dpll_disable(struct clk *clk); +/* Maximum DPLL multiplier, divider values for OMAP3 */ +#define OMAP3_MAX_DPLL_MULT 2048 +#define OMAP3_MAX_DPLL_DIV 128 + /* * DPLL1 supplies clock to the MPU. * DPLL2 supplies clock to the IVA2. @@ -255,7 +259,7 @@ static const struct clksel_rate div16_dpll_rates[] = { /* DPLL1 */ /* MPU clock source */ /* Type: DPLL */ -static const struct dpll_data dpll1_dd = { +static struct dpll_data dpll1_dd = { .mult_div1_reg = OMAP_CM_REGADDR(MPU_MOD, OMAP3430_CM_CLKSEL1_PLL), .mult_mask = OMAP3430_MPU_DPLL_MULT_MASK, .div1_mask = OMAP3430_MPU_DPLL_DIV_MASK, @@ -269,6 +273,9 @@ static const struct dpll_data dpll1_dd = { .autoidle_mask = OMAP3430_AUTO_MPU_DPLL_MASK, .idlest_reg = OMAP_CM_REGADDR(MPU_MOD, OMAP3430_CM_IDLEST_PLL), .idlest_bit = OMAP3430_ST_MPU_CLK_SHIFT, + .max_multiplier = OMAP3_MAX_DPLL_MULT, + .max_divider = OMAP3_MAX_DPLL_DIV, + .rate_tolerance = DEFAULT_DPLL_RATE_TOLERANCE }; static struct clk dpll1_ck = { @@ -276,6 +283,7 @@ static struct clk dpll1_ck = { .parent = &sys_ck, .dpll_data = &dpll1_dd, .flags = CLOCK_IN_OMAP343X | RATE_PROPAGATES | ALWAYS_ENABLED, + .round_rate = &omap2_dpll_round_rate, .recalc = &omap3_dpll_recalc, }; @@ -317,7 +325,7 @@ static struct clk dpll1_x2m2_ck = { /* IVA2 clock source */ /* Type: DPLL */ -static const struct dpll_data dpll2_dd = { +static struct dpll_data dpll2_dd = { .mult_div1_reg = OMAP_CM_REGADDR(OMAP3430_IVA2_MOD, OMAP3430_CM_CLKSEL1_PLL), .mult_mask = OMAP3430_IVA2_DPLL_MULT_MASK, .div1_mask = OMAP3430_IVA2_DPLL_DIV_MASK, @@ -331,7 +339,10 @@ static const struct dpll_data dpll2_dd = { .autoidle_reg = OMAP_CM_REGADDR(OMAP3430_IVA2_MOD, OMAP3430_CM_AUTOIDLE_PLL), .autoidle_mask = OMAP3430_AUTO_IVA2_DPLL_MASK, .idlest_reg = OMAP_CM_REGADDR(OMAP3430_IVA2_MOD, OMAP3430_CM_IDLEST_PLL), - .idlest_bit = OMAP3430_ST_IVA2_CLK_SHIFT + .idlest_bit = OMAP3430_ST_IVA2_CLK_SHIFT, + .max_multiplier = OMAP3_MAX_DPLL_MULT, + .max_divider = OMAP3_MAX_DPLL_DIV, + .rate_tolerance = DEFAULT_DPLL_RATE_TOLERANCE }; static struct clk dpll2_ck = { @@ -341,6 +352,7 @@ static struct clk dpll2_ck = { .flags = CLOCK_IN_OMAP343X | RATE_PROPAGATES, .enable = &omap3_noncore_dpll_enable, .disable = &omap3_noncore_dpll_disable, + .round_rate = &omap2_dpll_round_rate, .recalc = &omap3_dpll_recalc, }; @@ -371,7 +383,7 @@ static struct clk dpll2_m2_ck = { * Source clock for all interfaces and for some device fclks * REVISIT: Also supports fast relock bypass - not included below */ -static const struct dpll_data dpll3_dd = { +static struct dpll_data dpll3_dd = { .mult_div1_reg = OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL1), .mult_mask = OMAP3430_CORE_DPLL_MULT_MASK, .div1_mask = OMAP3430_CORE_DPLL_DIV_MASK, @@ -382,6 +394,9 @@ static const struct dpll_data dpll3_dd = { .recal_st_bit = OMAP3430_CORE_DPLL_ST_SHIFT, .autoidle_reg = OMAP_CM_REGADDR(PLL_MOD, CM_AUTOIDLE), .autoidle_mask = OMAP3430_AUTO_CORE_DPLL_MASK, + .max_multiplier = OMAP3_MAX_DPLL_MULT, + .max_divider = OMAP3_MAX_DPLL_DIV, + .rate_tolerance = DEFAULT_DPLL_RATE_TOLERANCE }; static struct clk dpll3_ck = { @@ -389,6 +404,7 @@ static struct clk dpll3_ck = { .parent = &sys_ck, .dpll_data = &dpll3_dd, .flags = CLOCK_IN_OMAP343X | RATE_PROPAGATES | ALWAYS_ENABLED, + .round_rate = &omap2_dpll_round_rate, .recalc = &omap3_dpll_recalc, }; @@ -545,7 +561,7 @@ static struct clk emu_core_alwon_ck = { /* DPLL4 */ /* Supplies 96MHz, 54Mhz TV DAC, DSS fclk, CAM sensor clock, emul trace clk */ /* Type: DPLL */ -static const struct dpll_data dpll4_dd = { +static struct dpll_data dpll4_dd = { .mult_div1_reg = OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL2), .mult_mask = OMAP3430_PERIPH_DPLL_MULT_MASK, .div1_mask = OMAP3430_PERIPH_DPLL_DIV_MASK, @@ -559,6 +575,9 @@ static const struct dpll_data dpll4_dd = { .autoidle_mask = OMAP3430_AUTO_PERIPH_DPLL_MASK, .idlest_reg = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST), .idlest_bit = OMAP3430_ST_PERIPH_CLK_SHIFT, + .max_multiplier = OMAP3_MAX_DPLL_MULT, + .max_divider = OMAP3_MAX_DPLL_DIV, + .rate_tolerance = DEFAULT_DPLL_RATE_TOLERANCE }; static struct clk dpll4_ck = { @@ -568,6 +587,7 @@ static struct clk dpll4_ck = { .flags = CLOCK_IN_OMAP343X | RATE_PROPAGATES, .enable = &omap3_noncore_dpll_enable, .disable = &omap3_noncore_dpll_disable, + .round_rate = &omap2_dpll_round_rate, .recalc = &omap3_dpll_recalc, }; @@ -843,7 +863,7 @@ static struct clk emu_per_alwon_ck = { /* Supplies 120MHz clock, USIM source clock */ /* Type: DPLL */ /* 3430ES2 only */ -static const struct dpll_data dpll5_dd = { +static struct dpll_data dpll5_dd = { .mult_div1_reg = OMAP_CM_REGADDR(PLL_MOD, OMAP3430ES2_CM_CLKSEL4), .mult_mask = OMAP3430ES2_PERIPH2_DPLL_MULT_MASK, .div1_mask = OMAP3430ES2_PERIPH2_DPLL_DIV_MASK, @@ -857,6 +877,9 @@ static const struct dpll_data dpll5_dd = { .autoidle_mask = OMAP3430ES2_AUTO_PERIPH2_DPLL_MASK, .idlest_reg = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST2), .idlest_bit = OMAP3430ES2_ST_PERIPH2_CLK_SHIFT, + .max_multiplier = OMAP3_MAX_DPLL_MULT, + .max_divider = OMAP3_MAX_DPLL_DIV, + .rate_tolerance = DEFAULT_DPLL_RATE_TOLERANCE }; static struct clk dpll5_ck = { @@ -866,6 +889,7 @@ static struct clk dpll5_ck = { .flags = CLOCK_IN_OMAP3430ES2 | RATE_PROPAGATES, .enable = &omap3_noncore_dpll_enable, .disable = &omap3_noncore_dpll_disable, + .round_rate = &omap2_dpll_round_rate, .recalc = &omap3_dpll_recalc, }; 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